Distribution of full motion video data has evolved from the early days of television broadcasting to meet viewer demand. Earliest video distribution was by point-to-point wiring between a camera and a video monitor. This was followed shortly thereafter by the proliferation of television broadcast stations transmitting fixed schedules of programming over the public air waves. In the 1960s, Community Antenna Television (CATV) systems were established, initially to provide off-air television signals to viewers in broadcast reception fringe areas. Under FCC regulation, the CATV industry was required to provide local access and original programming in addition to required off-air broadcast signal distribution. In response to the requirement for further television programming, several sources of cable network programming were established. Because of the wide bandwidth available on cable television systems, additional channels were made available for the new programming. However, the programming was generally prescheduled with the viewer left to tune into the designated channel at the appointed time to view a particular program.
To increase revenues, cable television systems initiated distribution of premium channels viewable only by subscribers having appropriate descramblers. The descrambler apparatus would receive premium channels and descramble the video and audio information to supply an output signal capable of reception on a standard television set. Pay per view programs were later provided. These programs included recently released movies, live concerts and popular sporting events. Subscribers wishing to view a pay-per-view program would place an order with the cable operator. In response, at the designated time, the subscriber's descrambler would be activated to permit viewing of the pay per view programming. However, the subscriber was restricted to viewing the programming at the scheduled time; there was no provision for providing programming to a subscriber at a time and date specified by the subscriber.
For example, Bessler et al., U.S. Pat. No. 4,755,872, describes an impulse pay-per-view system for use with a cable system having one-way addressable converters. Each of several central offices in a metropolitan area provide Automatic Number Identification (ANI) information representing the cable subscriber's phone number and the code representing the cable event to be viewed or cancelled. The data is sent asynchronously to a Telephone Communication Unit (TCU) located at a central office. The TCU sends the data asynchronously to a Telephone Communication Controller (TCC) located at a cable head end station. A system controller at the head end receives the data from each subscriber, locates a corresponding home terminal unit address, and performs other housekeeping activities. The controller then authorizes the home terminal unit to receive and descramble the requested program.
In the early 1980s, technological advances resulted in the proliferation of Video Cassette Recorders (VCR), thereby establishing a second channel for video programming distribution. Pre-recorded video programs were made available for sale and rental to VCR owners. With a VCR, the viewer could select from many titles available for sale and rental and could view the program when convenient. The VCR owner further had the capability to selectively view the programming using special functions of the VCR. Thus, the viewer could pause, fast forward, reverse and replay portions of the program at will. The penalty for this convenience, however, was the added inconvenience of making a trip to the local video sales and/or rental store, waiting for a popular video program to become available for sale and/or rental, returning home to view a video cassette, and the required trip back to the video store to return a rental tape.
To combine the benefits of both cable and video cassette distribution of programming, some cable operators have proposed programming-on-demand cable systems. For example, Walter, U.S. Pat. No. 4,506,387, describes a programming-on-demand cable system which allows a user to select a video program from a library of programs. The user transmits the program request over a dedicated fiber optic control cable to a central data station. The video program is then transmitted at a high, non-real-time rate over a fiber optic line network to a data receiving station at the user's location. A data receiving station then converts the received optical data back to electrical data and stores it for subsequent real time transmission to the user's television set.
Pooock et al., U.S. Pat. No. 5,014,125, describes an interactive television system for transmission of still frame video images and accompanying audio over a television system such as a cable network. A telephone network is used to establish a two-way communication path between a viewer's location and a central location. Information pertaining to the viewer, as well as commands related to the viewer selections for presentations and other data, are transmitted to the central location from a terminal at the viewer site by means of a telephone connection. The same telephone connection is used to transmit audio information from the central location to the viewer's terminal. The audio is combined with video information transmitted over another medium, such as a dedicated distribution cable, by the user terminal.
Clark et al., U.S. Pat. No. 4,761,684, describes a telephone access display system using a program data processor to operate a cable television system wherein a subscriber selects video information to be displayed on a common cable channel. The subscriber accesses a data processor using a telephone and selects video information to be broadcast over the cable system by inputting a digital code using the telephone touch tone pad. The data processor processes the signal generated, retrieves the video information from memory and places it in a queue to be broadcast simultaneously to all subscribers.
Gordon et al., U.S. Pat. No. 4,763,191, describes dial-up telephone network equipment for requesting an identified selection. A caller dials a "800" dial-a-view number for placing an order for a particular selection with a telephone network. Local and toll switching offices access a centralized data base to provide routing instructions to network services equipment which acknowledge the request and provide the request to cable television distribution equipment. ANI is forwarded along with a request to the program vendor equipment. The vendor equipment supplies the requested programming to the calling customer over a local cable company via an addressable descrambler at the calling customer's television.
Monslow et al., U.S. Pat. No. 4,995,078, describes a television broadcast system using dedicated cables for real-time transmission of a viewer-chosen program at a viewer requested time to the requesting viewer's television receiver. A viewer telephones a central location to request a particular program and viewing time. Respective customer service representatives answer the incoming calls and enter the information into a scheduling computer. Alternatively, an "auto dial" device can be used to request a program, the request being made directly to a voice response system. If the chosen movie has not yet been scheduled at the requested time, an appropriate cable channel is selected by the system and an operator activates a corresponding VCR to transmit the program at the requested time.
Lambert, U.S. Pat. No. 4,381,522, discloses a system in which a viewer can telephone a cable company central location and select a video program to be broadcast over one of the channels of a cable television system. A computer schedules the selected program, transmits the program at the scheduled time, and separately transmits a directory of all the scheduled programs on a dedicated directory channel. The viewer monitors the directory channel to determine when the requested recording is scheduled to be broadcast over the cable, and then tunes to the channel indicated at the scheduled time to view the program.
A disadvantage of programming-on-demand cable systems is the limited number of different programs which can be simultaneously supplied to viewers due to the small number of unused cable channels available for distribution of video programming. With the increase of premium and pay-per-view video programming available to the cable system operator, fewer channels remain free for viewer selected programming use. Further, the subscriber must forego desirable VCR type control of the video programming including pause, fast forward and rewind.
Telephone lines have been suggested as an alternate means of video distribution. Goodman et al., U.S. Pat. No. 5,010,399, describes a video transmission system for distributing video and control signals within a residence using existing telephone wiring. By filtering, simultaneous transmission of video and control signals over active telephone lines is possible without interference with telephone communications. The patent includes an extensive discussion of problems associated with the transmission of video signals over ordinary telephone wiring.
Kleinerman, U.S. Pat. No. 4,849,811, describes simultaneously sending audio and digitized single frames of video over standard telephone lines using Binary Frequency Shift Keying (BFSK). A frame grabber is used to convert the image to a standard NTSC signal for display on a monitor.
Thus, while simultaneous real-time distribution of a relatively small number of video programs is available over existing cable television systems, the capacity of the systems is limited by the available number of vacant channels on the system. Further, limited programming choice is offered by cable distribution methods since many subscribers must watch a particular selection to justify use of a dedicated channel for the duration of the video program. Still further, cable system distribution of video programs provides minimal programming flexibility on the part of the subscriber, again dependent on channel availability. Finally, no provisions are made to control the video in real time. Thus, the subscriber is without standard VCR type controls of the program material.
In contrast to cable distribution, systems using the PSTN are often bandwidth limited, providing only still frame or video conferencing capabilities. Because the systems use the PSTN only for connectivity between subscribers and/or between subscribers and Video Information Providers (VIPs), there is no capability for dynamic routing of digitized video without requiring dedicated leased, wide bandwidth circuits. The systems also fail to provide VCR type functional control of the programming.
Accordingly, an object of the invention is to provide video programming on demand using components of the PSTN.
Another object of the invention is to provide subscriber access to multiple sources of video programming over the PSTN.
Still another object of the invention is to provide real-time subscriber control of video programming delivery.
A still further object of the invention is to provide a selected video program to a subscriber within a predetermined short processing interval after initiation of a request.